Equal channel angular extrusion (ECAE) is widely investigated because of its potential to produce ultra-fine grained microstructures in magnesium alloys. It is crucial to understand the effect of die ...design on the deformation behavior, strain distribution and load requirement. In the paper new three-dimensional (3D) geometric models with different corner angles (90@uo,120@uo) and with or without inner round fillets in the bottom die were designed. Some important process parameters were regarded as the initial and boundary conditions used in DEFORM@u(TM)-3D software such as temperatures of the die and billet, the friction coefficient, etc. To ensure the convergence of the simulation, the geometrical and displacement conditions and reasonable convergence error limits, etc. have been considered. The deformation heterogeneity of ECAE was analyzed from the simulation and experimental results. The deformation homogeneity caused by fillets at outer corner was improved comparing with the die without fillets. The cumulate maximum strains decreased with the fillets of outer corner manufactured in ECAE die and the inner corner angles increasing. The requirement extrusion force decreased with the fillets made at outer corner angle in ECAE die. The analyses showed that better structures of ECAE die included appropriate outer corner fillets and the inner corner angle 90@uo. It was demonstrated that the predicted results were in good agreement with experiments and the theoretical calculation and the research conclusions from other literatures.
In order to understand the origin of high-temperature superconductivity in copper oxides, we must understand the normal state from which it emerges. Here, we examine the evolution of the normal state ...electronic excitations with temperature and carrier concentration in BiâSrâCaCuâOââδ using angle-resolved photoemission. In contrast to conventional superconductors, where there is a single temperature scale Tc separating the normal from the superconducting state, the high-temperature superconductors exhibit two additional temperature scales. One is the pseudogap scale T*, below which electronic excitations exhibit an energy gap. The second is the coherence scale Tcoh, below which sharp spectral features appear due to increased lifetime of the excitations. We find that T* and Tcoh are strongly doping dependent and cross each other near optimal doping. Thus the highest superconducting Tc emerges from an unusual normal state that is characterized by coherent excitations with an energy gap.
The pharmacokinetics of florfenicol were studied in both healthy (
n=9) and
Escherichia coli-infected (
n=27) broiler chickens following intravenous (i.v.), intramuscular (i.m.) and oral ...administration at a single dose of
30
mg/kg
bw
. Infection was induced artificially in broiler chickens (35
d) by an intraperitoneal injection with 1.3×10
9 colony-forming units of
E. coli. After i.v. administration in healthy and infected broiler chickens, the disposition kinetics of florfenicol were described by a bi-exponential equation. In diseased broiler chickens, a decrease in the elimination half-life and the apparent volume of distribution were found. The pharmacokinetic parameters such as total body clearance and the areas under curves of plasma concentrations were comparable in healthy and
E. coli infected chickens. Following i.m. and oral administration in infected chickens, the plasma concentration–time data for florfenicol were found to fit a single-compartment open model. The elimination half-lives (
t
1/2el) of florfenicol were 129(13) and 104(15)
min, the systemic bioavailability 87% and 71% after i.m. and oral administration.
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